When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I am driving a 74 F100 with a 390. I pulled the old thermostat last night. It didn't have the round copper do hickey on it. The replacement does. Which direction does the copper piece go?
I've seen a few come apart over the years and I've pulled a couple out of blocks I had apart, but I've never seen one get stuck in the pump or cause any problems, so I wouldn't lose any sleep over it. the only moving part in there is the WP and the inlets are so thin I don't think a very large piece could get to it.
Another good tip is to drill a 1/8 inch hole in the flat area of the stat before installing. It will help eliminate any air in the system, and allows a small amount of flow during the cold starts.
Mark